oh where to start.... if you want a REALLY geeky drink your'e looking at a pousse cafe, dealing with specific gravities, but there's always things like cafe diablo (coffee, booze and fire, what mose can you want)

then there's the discussion of the trace chemicals in gin (similar to opiates) or tequila (related to amphetamines) or the properties of absynthe in it's several forms... (mmm copper sulfate)

or we could wander into the thermal shifts associated with shaking or stirring a martini, and why a twist goes on at the end, not in the mix...

so your'e not gonna get more geeky than a pousse cafe. it's a ~7 layer layered drink with a different colour at each layer that are designed to be sipped slowly enjoying one or two layers at a time, all driver by density of different liquors. very difficult to pour well, very difficult to design, looks *really* cool.